First Earth-Directed CME of 2013

On Jan. 13, 2013, at 2:24 a.m. EST, the sun erupted with an Earth-directed coronal mass ejection or CME. Not to be confused with a solar flare, a CME is a solar phenomenon that can send solar particles into space and reach Earth one to three days later.

Experimental NASA research models, based on observations from the Solar Terrestrial Relations Observatory (STEREO) and the ESA/NASA mission the Solar and Heliospheric Observatory, show that the CME left the sun at speeds of 275 miles per second. This is a fairly typical speed for CMEs, though much slower than the fastest ones, which can be almost ten times that speed.

This visualization is constructed from a computer model run of the January 13, 2013 CME. The preliminary CME parameters were measured from instruments on the STEREO (the red and blue satellite icons) and SDO (in Earth orbit) satellites. The Enlil model was used to propagate those parameters through the solar system. From this model, they can estimate the strength and time of arrival of the CME at various locations around the solar system. This allows other missions to either safe-mode their satellites for protection, or allow them to conduct measurements to test the accuracy of the model.

When Earth-directed, CMEs can cause a space weather phenomenon called a geomagnetic storm, which occurs when they successfully connect up with the outside of the Earth's magnetic envelope, the magnetosphere, for an extended period of time. In the past, CMEs of this speed have not caused substantial geomagnetic storms. They have caused auroras near the poles but are unlikely to affect electrical systems on Earth or interfere with GPS or satellite-based communications systems.

Two active regions — named AR 11652 and AR 11654 by the National Oceanic and Atmospheric Administration (NOAA) — have produced four low-level M-class flares since Jan. 11. Solar flares are powerful bursts of light and radiation. Harmful radiation from a flare cannot pass through Earth's atmosphere to physically affect humans on the ground, however, when intense enough, they can disturb the atmosphere in the layer where GPS and communications signals travel. M-class flares are the weakest flares that can still cause some space weather effects near Earth. The recent flares caused weak radio blackouts and their effects have already subsided.

Enlil model for the Jan. 13, 2013 coronal mass ejection, plotted out to ten astronomical units (beyond the orbit of Saturn). The top view slices the data in the plane of the Earth's orbit and projects the planetary orbits onto that. The side view is a cross-section through the Sun-Earth line. The wedge-shape of the side view is because the Enlil model only extends above and below the solar equator by 60 degrees.